syzbot

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BUG: KCSAN: data-race in touch_atime / touch_atime

write to 0xffff88811b34e3d0 of 4 bytes by task 8947 on cpu 0:
 inode_set_atime_to_ts include/linux/fs.h:1687 [inline]
 inode_update_timestamps fs/inode.c:2034 [inline]
 generic_update_time fs/inode.c:2056 [inline]
 inode_update_time fs/inode.c:2076 [inline]
 touch_atime+0x1e8/0x340 fs/inode.c:2148
 file_accessed include/linux/fs.h:2663 [inline]
 shmem_file_read_iter+0x477/0x540 mm/shmem.c:3508
 copy_splice_read+0x442/0x660 fs/splice.c:363
 do_splice_read fs/splice.c:981 [inline]
 splice_direct_to_actor+0x290/0x680 fs/splice.c:1086
 do_splice_direct_actor fs/splice.c:1204 [inline]
 do_splice_direct+0xda/0x150 fs/splice.c:1230
 do_sendfile+0x380/0x650 fs/read_write.c:1370
 __do_sys_sendfile64 fs/read_write.c:1431 [inline]
 __se_sys_sendfile64 fs/read_write.c:1417 [inline]
 __x64_sys_sendfile64+0x105/0x150 fs/read_write.c:1417
 x64_sys_call+0x2bb0/0x2ff0 arch/x86/include/generated/asm/syscalls_64.h:41
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd2/0x200 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff88811b34e3d0 of 4 bytes by task 8946 on cpu 1:
 inode_get_atime_nsec include/linux/fs.h:1672 [inline]
 inode_get_atime include/linux/fs.h:1678 [inline]
 inode_update_timestamps fs/inode.c:2031 [inline]
 generic_update_time fs/inode.c:2056 [inline]
 inode_update_time fs/inode.c:2076 [inline]
 touch_atime+0x194/0x340 fs/inode.c:2148
 file_accessed include/linux/fs.h:2663 [inline]
 shmem_file_read_iter+0x477/0x540 mm/shmem.c:3508
 copy_splice_read+0x442/0x660 fs/splice.c:363
 do_splice_read fs/splice.c:981 [inline]
 splice_direct_to_actor+0x290/0x680 fs/splice.c:1086
 do_splice_direct_actor fs/splice.c:1204 [inline]
 do_splice_direct+0xda/0x150 fs/splice.c:1230
 do_sendfile+0x380/0x650 fs/read_write.c:1370
 __do_sys_sendfile64 fs/read_write.c:1431 [inline]
 __se_sys_sendfile64 fs/read_write.c:1417 [inline]
 __x64_sys_sendfile64+0x105/0x150 fs/read_write.c:1417
 x64_sys_call+0x2bb0/0x2ff0 arch/x86/include/generated/asm/syscalls_64.h:41
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd2/0x200 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x293d4433 -> 0x29d5dab3

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 8946 Comm: syz.2.2118 Not tainted syzkaller #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/14/2025
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